1. Field of the Invention
The present invention relates to an image recording apparatus which is capable of recording an image on a sheet transported along a transport passage.
2. Description of the Related Art
An image recording apparatus, which is capable of recording an image on a sheet, is provided with a transport passage for the sheet therein in most cases. In the image recording apparatus, the sheet is interposed by roller pairs, and thus the sheet is transported along the transport passage. For example, an ink jet printer is known as an image recording apparatus which is provided with a recording section for recording an image by discharging inks from an upward position to the sheet, and a platen provided under or below the recording section with a transport passage intervening therebetween for supporting the sheet.
A member for pressing the sheet (hereinafter referred to as “holding member”) is provided for the transport passage in order to move the sheet along the transport passage. The holding member prevents the sheet from being separated from the transport passage. The holding member is exemplified, for example, by a roller or a spur.
It is especially important to prevent the sheet from being separated from the transport passage when an image is recorded. Therefore, the holding member is used in order to press the sheet toward the platen. Accordingly, it is possible to prevent the sheet from the floating during the image recording. Japanese Patent Application Laid-open No. 2000-71532 discloses an ink jet recording apparatus which is constructed such that a sheet is pressed toward a platen by means of a plurality of projections 16 (holding members) provided in a direction perpendicular to a transport direction of the sheet.
Usually, the roller pairs for transporting the sheet are provided on the upstream side and the downstream side of the recording section respectively. When the sheet is transported, and the upstream end of the sheet passes through the upstream side roller pair, then the sheet is in a state of being interposed by only the downstream side roller pair. In the ink jet recording apparatus disclosed in Japanese Patent Application Laid-open No. 2000-71532, the holding members are provided on the just downstream side of the upstream side roller pair (feeding side driving roller 8 and registration roller 9). Therefore, when the upstream end of the sheet passes through the holding members, the sheet is interposed by only the downstream side roller pair (discharge side driving roller 20 and discharging spur 21).
In the case of the arrangement in which the plurality of holding members are provided in the direction perpendicular to the transport direction of the sheet as in the ink-jet recording apparatus disclosed in Japanese Patent Application Laid-open No. 2000-71532, the timings, at which the sheet is released from the pressing state effected by the holding members when the upstream end of the sheet passes completely through the holding members, are not completely simultaneous with each other in relation to all of the holding members in some cases. For example, when the sheet obliquely travels during the transport, and the pressing state, which is effected by the holding member disposed on the most outer side, is maintained to the last, then the force, with which the sheet is transported by the roller pair, acts as the angular moment (rotation moment) to rotate the sheet about the support point of the pressing position at which the sheet is pressed by the concerning holding member. For example, if the pressing state, which is effected by the holding member disposed at the left end as viewed from the downstream side, is maintained to the last, the sheet is rotated clockwise about the support point of the pressing position. Therefore, it is feared that the sheet may be more inclined with respect to the angle at which the sheet is to be transported. If the sheet is inclined, the image is recorded in a state of being inclined with respect to the sheet.